Carolyn Schofield has learned over the years not to be too afraid when it comes to letting her children get a little dirty.

The mother of three – 7, 9 and 12 years old – has dealt with kids getting sick despite vaccines, vitamin use and a proper diet.

The freshman McHenry County Board member has found that finding a balance between cleansing everything and doing nothing works best because kids will be kids.

“As a parent, whatever is going to happen is going to happen,” Schofield said, noting that her son has had H1N1, commonly known as swine flu, and pneumonia and mononucleosis in recent years. “You can teach them what they should be doing, but I am not going to keep them sheltered for the rest of their lives to avoid germs.”

Letting children play in the mud might just turn out to be good for their health, but opinions vary. The debate about whether to expose children to germs – known as the hygiene hypothesis – continues, with conflicting findings in two recent studies.

Evidence supporting how early exposure helps build a defense against autoimmune diseases such as hay fever or asthma was released in March by researchers at Brigham and Women’s Hospital, a teaching affiliate of Harvard Medical School.

Researchers studied the immune systems of germ-free mice and compared them with mice living in a normal environment with microbes. They found that germ-free mice had inflammation in the lungs and colon similar to asthma and colitis caused by hyperactivity of immune cells, or T cells, that had been linked to the same disorders in both species.

The study also revealed that exposing the germ-free mice to germs during their first week of life, but not later, created a normal immune system and prevented diseases.

“The hygiene hypothesis is just an idea. You want to be exposed to certain things in order to deal with them better when you are older,” Hazif said.

A study presented in late November by the International Scientific Forum on Home Hygiene agrees with the hygiene hypothesis that exposure to germs at an early age regulates the immune system, but went against the inclusion of germs that cause infectious diseases.

Improvements in sanitation, advancements to create cleaner food and water, and antibiotics have reduced germ exposure. Coupled with factors such as genetics, diet, pollution and stress, it makes humans more susceptible to allergies and chronic inflammatory diseases such as type 1 diabetes.

Good hygiene includes access to clean air and water, proper sewage and trash removal, and decent ventilation and indoor plumbing, Hafiz said.

The study suggests exposure to the “right” kind of microbes, not the pathogens that make people seriously ill.

Considered a more rational approach is “targeted hygiene,” according to the IFH study. That concept focuses on a proper hygiene habits instead of exposure.

“These studies are a great nutshell, but don’t necessarily translate,” he said. “No human lives in a completely sterile environment. There are so many differences between sterile, clean and poor sanitary conditions. And it makes a world of difference.”

Dr. Jeffrey Gindorf, a physician from Advocate Good Shepherd Hospital in Barrington, agreed.

“It would be impossible to sterilize any sort of environment completely,” he said. “That would prevent your immune system from learning what it needs to do to fight things off.”

Both studies recommend further research.

There is truth in both studies, Gindorf said.

“With the way our immune systems work, people need to be educated with what’s good and bad,” he said. “During routine existence, you are going to be exposed to things and your body is built to adapt to it. There are other situations where protocols have to be followed.”